Latch device requiring no complexly operating for preventing malfunction thereof

ABSTRACT

For latching an object member, a latch member is mounted on a base member so as to be movable between a first position where the latch member does not engage the object member and a second position where the latch member engages the object member. Movement of the latch member is controlled depending on the number of times of movement of a cam member which is mounted on the base member for following movement of the object member. A lock member is interposed between the base member and at least one of the cam member and the latch member. The lock member is movable between a lock position for limiting movement of at least one of the cam member and the latch member and a non-lock position for not limiting movement of at least one of the cam member and the latch member.

This application claims priority to prior Japanese patent applicationJP2005-216425, the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

This invention relates to a latch device for latching an object memberthat is movable in a predetermined direction.

Recently, it has been proposed to use, as an object member that isloadable and unloadable into and from an information processing device,a module in the form of a case and a CD, CD-ROM, DVD, HD, or the likethat is accommodated in the case (hereinafter referred to simply as a“module”). In order to enable the use of the module, the informationprocessing device has a housing formed with an insertion hole. Themodule is inserted into the insertion hole depending on necessity. Whenthe module is replaced with another or becomes unnecessary, it isremoved from the insertion hole.

The information processing device is provided with a latch device thatserves to lock the module in the state where it is inserted in theinsertion hole. The latch device of this type normally has a releasemechanism for releasing the module. The release mechanism has a movableoperating member to be operated from the exterior and releases themodule depending on an operation of the operating member. The releasedmodule can be easily removed from the information processing device.

The information processing device of the type is often carried withbeing contained in a bag or the like in a state where the module islatched in the insertion hole. During this carrying state, it is assumedas a particular case that the module is pushed by unexpected outsidepower or receives the impact by the fall of the information processingdevice. In the particular case, the module might be unlatched andtherefore removed from the information processing device. In order toprevent such removal of the module, the information processing devicemay be provided with a slide-type lock mechanism which is operated by ahand working to lock the module in a latch state thereof. However, thehand working is troublesome and has complication.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a latchdevice capable of preventing the malfunction thereof without complexlyoperating being necessary.

It is another object of the present invention to provide the latchdevice of the type described, in which a latch state thereof isautomatically locked when the latch device inclines.

Other object of the present invention will become clear as thedescription proceeds.

According to an aspect of the present invention, there is provided alatch device for latching an object member that is movable in apredetermined direction, the latch device comprising a base member, acam member mounted on the base member for following movement of theobject member, a latch member mounted on the base member and movablebetween a first position where the latch member does not engage theobject member and a second position where the latch member engages theobject member, a control mechanism coupled to the cam member and thelatch member for controlling movement of the latch member depending onthe number of times of movement of the cam member, and a lock memberinterposed between the base member and at least one of the cam memberand the latch member for locking the latch member at the second positionto prevent a release of the object member from the latch device, thelock member being movable between a lock position where the lock memberlimits movement of at least one of the cam member and the latch memberrelative to the base member and a non-lock position where the lockmember does not limit movement of at least one of the cam member and thelatch member relative to the base member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing the overall appearance ofan information processing device according to an embodiment of thepresent invention;

FIG. 2 is an explanatory diagram showing, on an enlarged scale, the mainpart of the information processing device of FIG. 1 along with a module;

FIG. 3A is a front view of a latch device used in the informationprocessing device of FIG. 1;

FIG. 3B is a left-side view of the latch device shown in FIG. 3A;

FIG. 3C is a bottom view of the latch device shown in FIG. 3A;

FIG. 4 is a front view showing, on an enlarged scale, the latch deviceof FIGS. 3A to 3C in the state where a cover member is detached;

FIG. 5 is a front view of an assembly formed by a base member, a cammember, and a return spring which are included in the latch device ofFIGS. 3A to 3C;

FIG. 6 is a bottom view of an assembly formed by a latch member and arod spring which are included in the latch device of FIGS. 3A to 3C;

FIG. 7A is a front view of the base member included in the latch deviceof FIGS. 3A to 3C;

FIG. 7B is a plan view of the base member shown in FIG. 7A;

FIG. 8A is a front view of the cam member included in the latch deviceof FIGS. 3A to 3C;

FIG. 8B is a bottom view of the cam member shown in FIG. 8A;

FIG. 9A is a front view of the latch member included in the latch deviceof FIGS. 3A to 3C;

FIG. 9B is a left-side view of the latch member shown in FIG. 9A;

FIG. 10A is a front view of the rod spring included in the latch deviceof FIGS. 3A to 3C;

FIG. 10B is a bottom view of the rod spring shown in FIG. 10A;

FIG. 11 is an explanatory diagram for explaining operation of a heartcam formed on the cam member of FIGS. 8A and 8B;

FIG. 12A is a front view like FIG. 4, showing the state where the cammember has slightly slid;

FIG. 12B is a front view like FIG. 4, showing the state where the cammember has further slid but a latch operation is not obtained;

FIG. 12C is a front view like FIG. 4, showing the state where the cammember has further slid and the latch operation is obtained;

FIG. 13 is a front view showing a portion of FIG. 5 in detail;

FIG. 14 is a perspective view of the portion illustrated in FIG. 13.

FIG. 15 is a perspective view showing a portion the latch member ofFIGS. 9A and 9B in detail as seen from a reverse side;

FIG. 16 is a view for describing variation of posture of the latchdevice illustrated in FIGS. 3A-3C;

FIG. 17 is a perspective view similar to FIG. 14, in which the postureof the latch device is changed;

FIG. 18 is a transparent perspective view showing a portion of the latchdevice of FIGS. 3A-3C; and

FIG. 19 is a transparent plan view of the portion illustrated in FIG.18.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, description will be given of an informationprocessing device according to an embodiment of the present invention.

The illustrated information processing device is designated by areference numeral 1 and is, for example, a laptop personal computer andcomprises a body portion 2 and a cover portion 3 attached to the bodyportion 2 so as to be openable and closable. The cover portion 3 has adisplay 4. The body portion 2 is provided with an operating portion 5such as a keyboard.

A housing of the body portion 2 is formed with an insertion hole 6 forenabling use of a module of a flat plate shape as an object member. Themodule is inserted into the insertion hole 6 depending on necessity.When the module is replaced with another or becomes unnecessary, it isremoved from the insertion hole 6 and separated from the informationprocessing device 1.

Referring also to FIG. 2, a module 7 is being inserted into theinsertion hole 6. Inside the body portion 2, a passage 8 is formed so asto extend in a horizontal first direction (predetermined direction) A1following the insertion hole 6. Therefore, the module 7 inserted intothe insertion hole 6 is located in the passage 8. The module 7 has aprojected portion 7 a and a recessed portion 7 b formed on a sidesurface thereof.

A latch device 10 is disposed on a lateral side of the passage 8 in ahorizontal second direction A2 perpendicular to the first direction A1.The latch device 10 serves to latch the module 7 in the inserted state.The latch device 10 is firmly fixed to the housing of the body portion2.

Referring also to FIGS. 3A to 12C, description will be given of astructure of the latch device 10.

In FIGS. 3A to 3C, the latch device 10 comprises a base member 11 and acover member 12 coupled to the base member 11. The base member 11 ismade of an insulating material or a metal material. The cover member 12is formed by a metal plate and fixedly engaged with the base member 11.

As seen from FIG. 4 where the cover member 12 is detached, a cam member13, a latch member 14, a rod spring 15, and a return spring 16 aredisposed between the base member 11 and the cover member 12. The cammember 13 and the latch member 14 are each made of an insulating resinor a metal material. On the other hand, the rod spring 15 and the returnspring 16 are each formed by a metal member having springiness. Forconvenience of illustration, the return spring 16 is exemplarilyillustrated.

In FIG. 5, the base member 11 has guide rails 11 a and 11 b on an uppersurface thereof. The cam member 13 is attached to the base member 11 soas to be slidable only in the first directions A1 along the guide rails11 a and 11 b. The cam member 13 may be called a sliding member. Thereturn spring 16 is a tension coil spring having opposite ends connectedto the base member 11 and the cam member 13, respectively, and urges thecam member 13 toward the side of the insertion hole 6 in the firstdirection A1. Part of the cam member 13 protrudes into the passage 8 asan operating projection 13 a.

On an upper surface of the cam member 13 is formed a heart cam 17 in theform of a generally heart-shaped groove that is substantially parallelto a predetermined plane spreading in the first and second directions A1and A2. A specific shape of the heart cam 17 will be described in detaillater.

The base member 11 further has a recessed portion 11 c and a projectedportion 11 d near the return spring 16. As shown in FIG. 4, the latchmember 14 is mounted on the upper side of the cam member 13. In thatevent, an end portion 14 a of the latch member 14 is disposed in therecessed portion 11 c. Then, a shaft hole 14 b of the latch member 14 isfittingly engaged with the projected portion 11 d. The end portion 14 aof the latch member 14 is made slightly smaller than the recessedportion 11 c so that the latch member 14 is swingable about theprojected portion 11 d as a fulcrum along the predetermined plane onlyin a certain angle range.

The latch member 14 has an engaging portion 14 c formed at the other endportion thereof, i.e. a free end thereof. The engaging portion 14 c canprotrude into the passage 8 from the base member 11 and the cover member12 substantially in the second direction A2 depending on a swing angleof the latch member 14. In other words, the latch member 14 is movablebetween a first position where the engaging portion 14 c does not engagethe module 7 and a second position where the engaging portion 14 cengages the module 7 in the first direction A1.

In FIGS. 4 and 6, the latch member 14 has a small hole 14 d near theshaft hole 14 b. The rod spring 15 has an intermediate portion 15 aextending between the cam member 13 and the latch member 14, a first endportion 15 b that is bent perpendicularly from one end of theintermediate portion 15 a and inserted into the small hole 14 d so as toengage the latch member 14 in its swing direction, and a second endportion 15 c that is bent from the other end of the intermediate portion15 a in a third direction (direction perpendicular to the sheet surfacein FIG. 4 or FIG. 6) perpendicular to the first and second directions A1and A2 so as to engage the heart cam 17 shown in FIG. 5.

In FIGS. 4 to 6, when the module 7 is inserted into the passage 8, theprojected portion 7 a of the module 7 engages the operating projection13 a in the first direction A1 to thereby move the cam member 13 againstthe biasing force of the return spring 16. According to the movement ofthe cam member 13, the second end portion 15 c of the rod spring 15moves following the heart cam 17. That is, the second end portion 15 cof the rod spring 15 is moved by the heart cam 17. Therefore, the rodspring 15 is herein also called a cam follower.

When the second end portion 15 c is moved by the heart cam 17, the rodspring 15 urges the latch member 14 toward one of the first and secondpositions through the first end portion 15 b. Specifically, when the cammember 13 starts moving, the rod spring 15 urges the latch member 14toward the second position. However, actual movement of the latch member14 is controlled by a control mechanism.

Details of the base member 11, the cam member 13, the latch member 14,and the rod spring 15 are shown in FIGS. 7A and 7B, FIGS. 8A and 8B,FIGS. 9A and 9B, and FIGS. 10A and 10B, respectively. The cam member 13has a projected portion 13 b formed on the upper surface thereof nearthe heart cam 17. On the other hand, on a lower surface of the latchmember 14 is formed a projected wall 14 e that engages the projectedportion 13 b. The latch member 14 is provided, near the free endthereof, with a lacking portion 14 f where the projected wall 14 e isnot formed. Further, the latch member 14 is formed with a window portion14 g passing therethrough. A combination of the projected portion 13 b,the projected wall 14 e, the lacking portion 14 f, the window portion 14g, and the heart cam 17 is referred to as the control mechanism.

Now, referring also to FIGS. 11 to 12C, description will be given of theoperation of the latch device 10 and the operation of the controlmechanism.

In FIG. 11, the heart cam 17 is hatched so as to be distinguished fromother portions. When the module 7 is not inserted in the passage 8, thesecond end portion 15 c of the rod spring 15 is located at a point a,i.e. a normal position, of the heart cam 17 and the latch member 14 isin the first position.

First, description will be given of a case where the module 7 is set inthe information processing device 1. When an operator inserts the module7 into the passage 8, the projected portion 7 a of the module 7 engagesthe operating projection 13 a of the cam member 13 in the firstdirection A1. When the module 7 is pushed, the cam member 13 moves. As aresult, the second end portion 15 c of the rod spring 15 moves along theheart cam 17 to reach a point b. During this movement, the rod spring 15urges the latch member 14 toward the second position. However, since theprojected portion 13 b of the cam member 13 is in engagement with theprojected wall 14 e of the latch member 14, the latch member 14 isretained in the first position. Therefore, the rod spring 15 graduallyincreases elastic bending to store energy during the movement. Herein, acombination of the projected portion 13 b and the projected wall 14 ewill be referred to as a first engaging mechanism.

At the groove bottom of the heat cam 17, there is formed, from the pointb to a point c, a steep ramp 17 a that gradually raises the second endportion 15 c of the rod spring 15 following the sliding movement of thecam member 13. Further, from the point c to a point d of the heart cam17, there is formed a large height difference 17 b that rapidly lowersthe second end portion 15 c of the rod spring 15. In this manner, aprotuberant portion is defined at part of the heart cam 17 by the steepramp 17 a and the large height difference 17 b.

When the cam member 13 is further moved by the module 7, the second endportion 15 c of the rod spring 15 gets on the protuberant portion alongthe heart cam 17 to reach the point c. In this event, the intermediateportion 15 a of the rod spring 15 is inserted into the window portion 14g of the latch member 14. Simultaneously with or immediately after this,the projected portion 13 b and the projected wall 14 e disengage fromeach other. That is, the projected portion 13 b reaches a positionconfronting the lacking portion 14 f. However, an edge of the windowportion 14 g of the latch member 14 is locked by the intermediateportion 15 a of the rod spring 15 in this event, the latch member 14continues to be retained at the first position or near that position.Therefore, the rod spring 15 maintains the large stored energy. Herein,the projected portion 13 b and the edge of the window portion 14 gcooperatively constitute an engaging portion or a second engagingmechanism. Further, a combination of the steep ramp 17 a and the lackingportion 14 f will be referred to as an engagement switching mechanismthat switches from the first engaging mechanism to the second engagingmechanism following the movement of the heart cam 17.

When the cam member 13 is further moved by the module 7, the second endportion 15 c of the rod spring 15 passes through the large heightdifference 17 b of the heart cam 17 to reach the point d. The second endportion 15 c is rapidly lowered upon passing through the large heightdifference 17 b so that the intermediate portion 15 a of the rod spring15 disengages from the window portion 14 g of the latch member 14. Then,the latch member 14 is completely released and therefore rapidly movestoward the second position by the stored energy of the rod spring 15.Herein, the large height difference 17 b of the heart cam 17 serves asan engagement release mechanism that releases the operation of theforegoing second engaging mechanism.

As a result, the engaging portion 14 c of the latch member 14 protrudesinto the passage 8 and is inserted into the recessed portion 7 b of themodule 7. Therefore, the module 7 is disposed at a predeterminedposition of the information processing device 1 and locked by the latchmember 14 so as to be prevented from detachment.

Upon the disengagement of the intermediate portion 15 a of the rodspring 15 from the window portion 14 g of the latch member 14, thesecond end portion 15 c of the rod spring 15 is urged to move in adirection opposite to the latch member 14 by the stored energy of therod spring 15. However, the movement thereof is restricted due to itscollision with a wall portion of the cam member 13 at a point h of theheart cam 17.

When the module 7 is locked by the latch member 14, the insertion forceof the module 7 may be released. When the insertion force of the module7 is released, the cam member 13 is slightly returned by the returnspring 16 so that the second end portion 15 c of the rod spring 15 isstopped in the state where it is located at a point e. In addition, theprojected portion 13 b of the cam member 13 confronts the projected wall14 e of the latch member 14 in the second direction A2. Therefore, thelatch member 14 is prevented from returning to the first position fromthe second position.

Now, description will be given of a case where the module 7 is removedfrom the information processing device 1. In this case, the operatorslightly pushes the module 7. Then, the second end portion 15 c of therod spring 15 moves to a point f. In that event, the latch member 14 ispushed by the second end portion 15 c of the rod spring 15 so as to bemoved and returned to the first position. As a result, the projectedportion 13 b of the cam member 13 enters the lacking portion 14 f of thelatch member 14.

When the pushing force to the module 7 is released, the second endportion 15 c of the rod spring 15 moves to a point g. From this point,the projected portion 13 b of the cam member 13 engages the projectedwall 14 e to provide the state where the first engaging mechanism isoperated. Thereafter, the cam member 13 is returned to the initialposition by the return spring 16. Therefore, the module 7 is pushed outof the passage 8 by the operating projection 13 a of the cam member 13.In this event, the second end portion 15 c of the rod spring 15 isreturned to the point a, i.e. the normal position.

In order to prevent backward movement of the second end portion 15 c ofthe rod spring 15, the heart cam 17 is formed with low stepped portions17 c and 17 d, a gentle ramp 17 e, and so on at several portions.

The rod spring 15 also has a function as an elastic member to urge andmove the latch member 14 in the direction crossing the slide direction(A1) of the cam member 13.

Referring to FIGS. 13-19 in addition, the latch device 10 will bedescribed in detail.

In FIGS. 13 and 14 showing only a portion of FIG. 5 in detail, the basemember 11 is formed with a guide groove 100 and two projections 100 a.The guide groove 100 has a shape including a slant surface 100 b. Ametal ball 102 is placed in the guide groove 100. The guide groove 100has a depth determined so that the metal ball 102 does not overflow fromthe guide groove 110. The metal ball 102 serves to lock the lath memberat the second position. In other words, the metal ball 102 is referredto as a lock member for locking a latch state of the latch device 10. Inthe manner which will later become clear, the metal ball 102 is movablebetween a lock position of the latch device 10 and an unlock positionthereof.

In FIG. 15, the latch member 14 is formed with two escaping groove 103for escaping the projections 100 a. Thus, the latch device 10 isdesigned so that, when rotated, the latch member 14 can smoothly bemoved without being interfered to the base member 11.

The latch device 10 is normally kept to have a horizontal posture. Thelatch device 10 horizontal is depicted by a reference numeral 10A inFIG. 16. In this state, the metal ball 102 is placed in the unlockposition, that is, a deepest part of the guide groove 100 by an actionof the slant surface 100 b of the guide groove 100.

It will be assumed here that the latch device 10 is inclined towards anarrow 110 to make the slant surface 100 b be parallel to a horizontalplane. The latch device 10 inclined is depicted by a reference numeral10B in FIG. 16. When the latch device is further inclined so that theslant surface 100 b exceeds the horizontal plane, the metal ball 102moves along the guide groove 100 to stop at the lock position, that is,a position adjacent to the projections 100 a clearly illustrated in FIG.17. When stopped at the lock position, the metal ball 102 is placed in arecessed portion 103 b formed in a wall portion 103 a which is betweenthe escaping grooves 103 of the latch member 14. As a result, the metalball 102 is interposed between the projections 100 a of the base member11 and the wall portion 103 a of the latch member 14.

It will be assumed as a particular case that external force acts to thecam member 13 as shown by an arrow 120 in FIG. 19. In the particularcase, with being dependent on the heart cam 17 of the cam member 13, thelatch member 14 starts rotating thereof as shown by an arrow 130 in FIG.19. However, the latch state of the latch device 10 is not released.This is because the metal ball 102 is pinched between the projections100 a of the base member 11 and the wall portion 103 a of the latchmember 14 to thereby be limited a movable range thereof. In this event,the cam member 13 receives force towards a direction shown by an arrow140 in FIG. 19.

It is noted here that the arrows 120, 130, and 140 are directeddifferent to one another. This means that the external force isdispersed to act as small force to various parts or portions. As will bedescribed above, the base member 11 and the latch member 14 are fittedto each other with concavity and convexity structure. Inasmuch as theexternal force is dispersed, the concavity and convexity structure canbe designed small.

Since the external force is transmitted to the rod spring 15 from thecam member 13 though the heart cam 17, the biggest load acts on the rodspring 15 and the heart cam 17. Accordingly, it is preferable to providesufficient strength in each of the rod spring 15 and the heart cam 17.For this purpose, the heart cam 17 is provided with an additional groove104 which receives the rod spring 15 when the load exceeds a prescribedvalue. When the external force is released, the rod spring 15 is escapedfrom the additional groove 104 by the return spring 16. Therefore, thelatch device 10 is returned to the latch state.

While the present invention has thus far been described in connectionwith a single embodiment thereof, it will readily be possible for thoseskilled in the art to put this invention into practice in various othermanners. For example, it may be designed such that when the module 7 isinserted, an insertion end thereof, instead of the projected portion 7 athereof, engages the operating projection 13 a of the cam member 13.Further, the latch member 14 may be formed with a non-through recessedportion instead of the through window portion 14 g. Further, thegenerally heart-shaped groove forming the heart cam 17 may be inclinedwith respect to the foregoing predetermined plane. In addition, thepresent invention is applicable not only to an information processingdevice such as a computer, but also to various devices or apparatuseseach required to latch a movable object member. It is a matter of coursethat use may be made of a plastic ball or the like instead of using themetal ball. Such a ball may be used at least one of between the latchmember 14 and the cam member 13 and between the base member 11 and thecam member 13 in the manner similar to the above-mentioned metal ball100.

1. A latch device for latching an object member movable in apredetermined direction, the latch device comprising: a base member; acam member mounted on the base member for following movement of theobject member; a latch member mounted on the base member and movablebetween a first position where the latch member does not engage theobject member and a second position where the latch member engages theobject member; a control mechanism coupled to the cam member and thelatch member for controlling movement of the latch member depending onthe number of times of movement of the cam member; and a lock memberinterposed between the base member and at least one of the cam memberand the latch member for locking the latch member at the second positionto prevent a release of the object member from the latch device, thelock member being movable between a lock position where the lock memberlimits movement of at least one of the cam member and the latch memberrelative to the base member and a non-lock position where the lockmember does not limit movement of at least one of the cam member and thelatch member relative to the base member.
 2. The latch device accordingto claim 1, wherein the lock member comprises a ball which is placed atthe non-lock position when the latch device has a desired posture, theball moving from the non-lock position towards the lock position whenthe latch device is inclined to exceed a predetermined angle from thedesired posture.
 3. The latch device according to claim 1, wherein thecam member has a hart cam, the control mechanism comprising a camfollower engaged with the heart cam and the latch member to urge thelatch member following movement of the heart cam.
 4. The latch deviceaccording to claim 3, wherein the control mechanism controls movement ofthe latch member depending on a shape of the heart cam in addition tothe number of times of movement of the cam member.
 5. The latch deviceaccording to claim 3, wherein the cam follower comprises a rod springcomprising a first end portion engaged with the latch member and asecond end portion engaged with the heart cam.
 6. The latch deviceaccording to claim 5, wherein the rod spring further comprises anintermediate portion substantially extending in the predetermineddirection, the first end portion located at one end of the intermediateportion and engaging the latch member in its swing direction, the secondend portion being bent perpendicularly from the other end of theintermediate portion and engaging the heart cam.
 7. The latch deviceaccording to claim 6, wherein the heart cam has a generally heart-shapedgroove formed on the cam member, the generally heart-shaped groove has aprotuberant portion defined by a ramp that gradually raises the secondend portion following sliding movement of the cam member and a heightdifference that rapidly lowers the second end portion, and the latchmember has an engaging portion that engages the intermediate portionwhen the second end portion gets on the protuberant portion, to therebyretain the latch member at the first position.
 8. The latch deviceaccording to claim 1, wherein the control mechanism comprises: a latchlocking mechanism coupled to the latch member for forcibly locking thelatch member at the first position; and a latch release mechanismcoupled to the latch locking mechanism and the corn member for releasingoperation of the latch locking mechanism depending on the movement ofthe cam member.
 9. The latch device according to claim 1, wherein thecontrol mechanism comprises: a first engaging mechanism for retainingthe latch member at the first position by engagement between the latchmember and the cam member; a second engaging mechanism for retaining thelatch member at the first position by engagement between the latchmember and the intermediate portion; an engagement switching mechanismfor switching from the first engaging mechanism to the second engagingmechanism following the movement of the cam member; and an engagementrelease mechanism for releasing operation of the second engagingmechanism following the movement of the cam member.
 10. The latch deviceaccording to claim 1, wherein the latch member is swingable about afulcrum at one end thereof relative to the base member in apredetermined plane, the cam member being disposed between the latchmember and the base member and attached to the base member so as to beslidable in the predetermined direction, the cam follower comprising arod spring having a first end portion engaged with the latch member anda second end portion engaged with the heart cam, the latch devicefurther comprising a return spring urging the cam member toward one sidein the predetermined direction.
 11. The latch device according to claim10, further comprising a cover member coupled to the base member,wherein the cam member, the latch member, the rod spring, and the returnspring are disposed between the base member and the cover member.